The objective of this research is to develop ICP-BP Waveform Analysis into a clinically useful diagnostic and analytical tool. Spectral analysis of ICP-BP Waveforms of cats under controlled surgical simulation of pathophysiological conditions, and of ICU patients being monitored for treatment of various causes of an increased ICP will be performed. The cats will undergo experimental procedures to increase ICP by ventricular infusion, epidural balloon inflation, and induced cerebral edema. The recorded waveforms will be analyzed using techniques of systems analysis. A file of waveforms and spectral analyses of neurosurgical patients will also be developed. This file will be used to verify in patients the clinical value of the laboratory experiments. It is expected that specific spectral characteristics of waveform will correlate to the clinical status of the intracranial cavity. This knowledge should greatly enhance the management of neurosurgical patients undergoing ICP monitoring in an Intensive Care Unit. Preliminary results indicate waveform change with pathology and ICP level.